Electrolytic rust removal - please add your experiences!

[kai]

I snipped this question from a thread (on another topic):

Originally Posted by RobT

Could you describe the process of electrolytic rust removal or direct me to a source of information for same? I would really like to try out the method.

Hi Rob,

It's really not complicated and you can adapt this method to your specific needs. A practicable introduction for home use can be found at http://www.htpaa.org.au/article-electro.php and you can google for loads of additional info.

I've found it not necessary to be too finicky with the degreasing step (just wash with soap) - you can always go for a second electrolysis if there happen to be persisting rust spots (discard the electrolysis solution after use if there's oil floating at the surface). As of now I have used this method only for fairly easy cleaning jobs and it worked out fine. So, not much else to add from yours truly.

However, I have acquired a few blades which really need preservation yet I have postponed finishing them due to complications like metal inlays (silver as well as brass) or problematic disassembly. Thus, I'd love to hear others' experiences, especially in more difficult cases!

Regards,
Kai

[RobT]

kai,
Thanks for info and the link to the site. I bought a battery charger today and, at this writing have an African arm dagger bubbling away in a solution of water and epsom salts (magnesium sulfate USP). I didn't have any washing soda (sodium carbonate) but I figured for the purposes of conductivity that a salt is a salt is a salt. Judging from the rust scum floating on the surface of the solution, the process is working. this evening I will remove the dagger from the solution and give it a quick scrub down with an abrasive pad to see how much rust five hours in the bath will remove. I took "before" pictures of the blade. It looks as if it was stored in a New England boat house for a few winters. It is rust city. When I first picked up the piece in the dealer's booth, it was rusted shut in the scabbard. When I finally managed to work it free, the dealer took one look at the blade and gave it to me for free. At one time this was a good quality piece so hopefully I can restore it to some semblance of its former condition. I don't think I can do much to degrade it further.
Sincerely,
RobT

[kai]

Hi Rob,

You're welcome!

Originally Posted by RobT

I bought a battery charger today and, at this writing have an African arm dagger bubbling away in a solution of water and epsom salts (magnesium sulfate USP). I didn't have any washing soda (sodium carbonate) but I figured for the purposes of conductivity that a salt is a salt is a salt.

Well, baking soda works just as well. Be careful with using any other salts since there may be unexpected side effects (including development of poisonous gases). Epsom may be fine but still it might speed up new rust after the power has been turned off. Whatever salt is used, it is really paramount to immediately apply some rust prevention anyway - right after srubbing and thoroughly drying the blade!

I took "before" pictures of the blade. It looks as if it was stored in a New England boat house for a few winters.

Let them come!

At one time this was a good quality piece so hopefully I can restore it to some semblance of its former condition.

I'm sure the blade will be ok (i.e. better than before ). Let's hope that there's not too much pitting though.

Regards,
Kai

[RobT]

kai,
Five hours in the electrolyte solution removed all red rust from the blade. This is pretty remarkable considering that the entire blade surface was colored various shades of red. Although there are patches of bare grey steel, most of the blade is covered with black oxide (magnetite Fe3 O4 ?). This is proving very difficult to remove, especially since the blade is severely pitted. I don't know if another stint in the electrolyte bath would help. Any suggestions? (The methods given in the article aren't suitable for blades.) On a positive note, I have seen no fresh signs of rusting. In any event, I intend to work on the blade a bit more before posting before and after pictures.
Sincerely,
RobT

[Ann Feuerbach]

From an archaeological conservators point of view...electrolitic reduction was tried alot in the 1980s (I think that was the decade). It was discarded as you loose alot of technological information, thus reducing the authenticity of the piece. Try a conservation site for more information. Do a search using ww.Dogpile.com and I think it is the AIC site that has journals you can look up online. Basically, while it might work, it is should not be recommended.

[Ann Feuerbach]

For a more positive suggestion, air abrasion is the preferred method these days.

[RobT]

Hi All,
I put the experimental blade in the electrolyte bath for a second time and left it overnight. (This before Ann's warning.) No sound metal appears to have been removed but frankly, the blade is in such sad shape that it's hard for me to tell. When I post the before and after pictures this weekend perhaps other forum members can point out things that I have missed. My thanks to Ann for the warning. I will certainly look up the recommended web sites for further information. By the way, what is this air abrasion? A kinder, gentler sandblasting perhaps? Is there a website that gives a detailed description of this method and the necessary equipment?
Sincerely,
RobT

[Ann Feuerbach]

Yeah, basically sandblasting with glass pellets (I forgot at this second what they are technically called) micro beads?

[Ian]

Another very good abrasive that does not remove sound metal is a commericial product called "Black Beauty," which I think is a synthetic material. It is gentler than sand that will take off healthy iron or steel if you're not careful.

There are many other forms of abrasives used for blasting, including such things as peanut shells, ground corn husks, glass beads, plastic beads, etc.

Abrasive blasting should be done whenever possible in an enclosed cabinet to avoid inhaling the very fine particles that are produced. This is particularly important for sand, which contains silica and can cause serious lung disease. Abrasive blasting on large pieces done outside an enclosed box requires that the operators wear proper respirators, eye protection, etc. to protect themselves from the dust. It is also a noise hazard, so hearing protection should be used too.

Abrasive blasting is not a difficult procedure but it needs to be done with the proper safety precautions.

Ian.

[RobT]

Hi All,
I am posting before and after pictures of two African daggers that have undergone electric rust removal. The first, a Hadendoa dagger, has been very badly consumed by corrosion. The second, a Tuareg dagger, was rusted on the upper half of the blade and only lightly pitted. After immersion in the electrolyte bath, both blades were rubbed down with a 3M abrasive pad. Even though Ann cautions against this method, it appears to me that the proceedure yields good results. Perhaps the preservation needs of archaeologists are different than those likely to be encountered by the average blade collector? I would appreciate it if members would take a look at the results and offer feedback. I would especially welcome the advice from members that have successfully gotten rid of the grey staining that remains on blades once the rust has removed. Is there perhaps a poltice of some kind that can take care of this? The last image in this post is the Hadendoa sheath. For those that wish to see the Tuareg sheath, it can be found on the thread titled "Large Sudanese Dagger for Comment" by Louieblades.
Sincerely,
RobT

[Ian]

Rob:

Gentle abrasive blasting will get you back to white metal, removing rust, stain, patina with great ease. Protect the handles and anything else you don't want to abrade.

Ian.

[Ann Feuerbach]

The result is very good. You are correct to point out that the needs and requirement for restoration and conservation can be very different. I will be looking into this more again, when I get time. I will let you know the results so each of us can decide when it is an appropriate treatment, and when not. By the way, nice blades.
Ann

[kai]

Thanks, Ann, for the warning.

I have yet to finish my homework. However, the problems which I have seen being reported seem to center on heavily encrusted marine antiques and I'm still not sure how much this bears on removing relatively thin rust from steel blades. At least one should try to keep electrolysis as short as possible.

Regards,
Kai

[kai]

Originally Posted by RobT

Although there are patches of bare grey steel, most of the blade is covered with black oxide (magnetite Fe3 O4 ?). This is proving very difficult to remove, especially since the blade is severely pitted.

Thanks for your updates, Rob!

I'm not sure I'd want to remove all of this patina.

If you're desperate enough, you could try etching with fruit acids (e. g. lemon juice) which tends to remove magnetite also (but will also etch the blade, i. e. make it rougher. It also works in pitted areas but don't expect wonders - keep brushing the blade from time to time to remove losened sludge. Fruit acids will also darken the blade and, thus, may make pitted areas less noticeable.

Regards,
Kai

[RobT]

Hi All,
Thanks to you all for your informative responses. With Ian's caution about possible lung damage due to abrasive dust inhalation firmly in mind I intend to build a blasting box and get a compressor. Does anyone know what size of compressor (tank size and flow rate) that I would need? Money is an important consideration as is portability since I would like to use the unit around the house. Also, does anyone know what kind of attachments (like nozzles and abrasive canisters) I will need? I intend to check out the Black Beauty abrasive that Ian mentioned. Perhaps that company can provide some information also.
Ann, I very much look forward to your analysis of the differing needs for restoration and conservation. Thanks too for your compliment on my blades.
Kai, thanks for starting this ball rolling. Regarding your last post on this thread however, I must say that, unless the entire blade is uniformly black, the pits will show up loud and clear. I know this because I just spent about two years polishing the staining out of a wootz Kurdish Jambiya. (It was ok once but I'll never do it again. Life is too short.) The pitting and metal loss to this blade was severe but when the blade was polished mirror bright prior to etching, the pitting didn't look half as bad as when the blade was stained. Now that the etching is done the blade looks fairly respectable. This is why I'm so eager to pursue non-damaging methods to clean blades quickly and effectively.
Sincerely,
RobT

[kai]

Originally Posted by RobT

With Ian's caution about possible lung damage due to abrasive dust inhalation firmly in mind I intend to build a blasting box and get a compressor.

To those who are still unconvinced: Please do yourself a favor and google for silicosis! BTW, there's a host of severe health hazards associated with just about any sort of fine particles (i. e. "dust") - which also includes wood working!

[/QUOTE] unless the entire blade is uniformly black, the pits will show up loud and clear. I know this because I just spent about two years polishing the staining out of a wootz Kurdish Jambiya. ... The pitting and metal loss to this blade was severe but when the blade was polished mirror bright prior to etching, the pitting didn't look half as bad as when the blade was stained.[/QUOTE]
Yeah, pitting really is a nasty damage which tends to spoil the looks of a blade no matter what. That's why sellers usually don't touch rust encrustations - restoration tends to be a long, long uphill battle...

Rob, do you have before/after pics of that jambiya?

One possibility would be to protect the pit(tings?) with wax/etc. and only stain the smooth blade surface. That still will make the pitted areas more noticeable than in mirror polish: However, IMVHO some blades just look "wrong" if not stained properly...

Regards,
Kai